Speaking to AFP, a number of astronomers have challenged the Harvard scientists’ suggestions.

“Like most scientists, I would love there to be convincing evidence of alien life, but this isn’t it,” said Dr Alan Fitzsimmons of Queens University Belfast.

“It has already been shown that its observed characteristics are consistent with a comet-like body ejected from another star system.

“And some of the arguments in this study are based on numbers with large uncertainties.”

Another well-known astrophysicist, Dr Katie Mack from North Carolina State, was critical of the claim on Twitter.

The thing you have to understand is: scientists are perfectly happy to publish an outlandish idea if it has even the tiniest *sliver* of a chance of not being wrong. But until every other possibility has been exhausted dozen times over, even the authors probably don’t believe it.

“The thing you have to understand is: scientists are perfectly happy to publish an outlandish idea if it has even the tiniest *sliver* of a chance of not being wrong.

“But until every other possibility has been exhausted dozen times over, even the authors probably don’t believe it.”

In a letter in The Astrophysical Journal Letters, Dr Shmuel Bialy and Dr Avi Loeb claimed that Oumuamua could be a spacecraft pushed along by light falling on its surface – a theoretical form of space transportation known as a “light sail”.

AFP asked Dr Bialy if he believed his claim. He admitted: “I wouldn’t say I ‘believe’ it is sent by aliens, as I am a scientist, and not a believer, I rely on evidence to put forward possible physical explanation for observed phenomena.”

Dr Loeb, who is the chairman of Harvard’s astronomy department, told NBC News: “It is impossible to guess the purpose behind Oumuamua without more data.”